A heat-resistant resin is utilized in an interlayer dielectric film and a surface protective coat (buffer coat alpha ray shielding film) in the semiconductor field. The heat-resistant resin is inferior in pattern processing and is therefore converted into an insoluble and infusible heat-resistant resin by forming a coating film using a heat-resistant resin precursor having high solubility in an organic solvent, performing pattern processing using a photoresist and thermocuring the precursor. It has recently been made a trial of simplifying a photoresist step using a negative or positive photosensitive heat-resistant resin precursor composition which itself is capable of performing pattern processing.
As a negative photosensitive heat-resistant resin precursor composition in which the exposed area is remained after development, for example, there has been known a composition prepared by adding an amino compound containing an organic group capable of being dimerized by actinic radiation or a polymerizable carbon-carbon double bond, or a quaternized salt thereof to polyamic acid, a composition prepared by adding acrylamides to polyamic acid, or a polyimide precursor having a carbon-carbon double bond group in the side chain or the main chain of a polymer.
As a positive heat-resistant resin precursor composition in which the exposed area is dissolved by development, for example, there has been known a composition prepared by adding quinonediazide to polyamic acid, a composition prepared by adding quinonediazide to a soluble polyimide having a hydroxyl group, or a composition prepared by adding quinonediazide to polyamide having a hydroxyl group.
As these resin precursor compositions, for example, there have been developed a composition prepared by adding a phenolic hydroxyl group-containing thermocrosslinking compound to a poyamidate ester and/or a polyamic acid polymer (see, for example, Japanese Unexamined Patent Publication (Kokai) No. 2002-328472 (claim 1)), a composition prepared by adding a compound having two or more alkoxymethyl groups and a phenolic hydroxyl group in the molecule or a compound having plural methylol groups and a phenolic hydroxyl group to a polyimide precursor or polyimide which is soluble in an aqueous alkali solution, a composition prepared by adding an iodonium salt as a dissolution inhibitor to a poyamidate ester, a composition prepared by adding an iodonium salt as a dissolution inhibitor to a polyamide, a composition prepared by adding a photo acid generator and a vinyloxy group-containing compound to a polyamidate ester, a composition prepared by adding a photo acid generator to a polyamidate ester having an acid dissociable group, and a composition prepared by adding a compound capable of accelerating solubility through an action of a photo acid generator and an acid to a polybenzooxazole precursor.
With recent miniaturization of wiring, fine processability of an isolated pattern having a size of 5 μm is required to a heat-resistant resin. However, a conventional resin composition had a problem that a developing solution penetrates into a space between a pattern and a substrate upon development, and an isolated pattern is peeled, or peeled in an acceleration test at high temperature and high humidity because of poor adhesion property between the pattern and the substrate after curing.
As a method of improving the adhesion property after development and curing, for example, a method of preliminarily subjecting the side of a substrate to a surface treatment such as an oxygen plasma treatment is known. However, it was required by the industrial field to omit such a complicated treatment. Therefore, a method of copolymerizing a photosensitive resin with a silicone component (see Japanese Unexamined Patent Publication ((Kokai) No. 6-157875) and a method of adding a silane coupling agent to a photosensitive resin composition are proposed (see Japanese Unexamined Patent Publication (Kokai) No. 2003-76017, and Japanese Unexamined Patent Publication (Kokai) No. 9-146274). However, there was a problem that, when a particularly effective aminosilane-based compound is added as a silane coupling agent, a photosensitive component is decomposed and thus storage stability of the solution drastically deteriorates. Also, when a siliconediamine is copolymerized, it is impossible to cope with a problem that a fine pattern is peeled upon development.